Electrically conductive material



Feb. 16, 1954 c. J. FORD ELECTRICAL-LY CONDUCTIVE MATERIAL 2SheefLs-Sheet 1 Filed Jan. 20, 1950 Charles J Ford ATTORNEY Feb. 16,1954 c. J. FORD 2,669,646

ELECTRICAL-LY CONDUCTIVE MATERIAL Filed Jan. 20., 1950 2 Sheets-Sheet 2FIG. 4

7 FIG. 6 W

- Charles J. Ford 25 'III/IIIIIIII/IIIIIIII.

FlG. 5 Ki ATTO R N EY Patented Feb. 16, 1954 ELECTRICALLY CONDUCTIVEIVIATERIAL Charles J. Ford, Akron, Ohio, assignor, by mesne assignments,to The Goodyear Tire & Rubber Company, a corporation of Ohio ApplicationJanuary 20, 1950, Serial No. 139,551

1 Claim. 1

The present invention relates to an improved form of electricallyconductive material and the method of making the same. Moreparticularly, the invention is concerned with a composite form ofelectrically conductive material embodying integrally formed conductorstherein. v

An electrically conductive material of the type with which the teachingsof the present invention are advantageously employed is any flexiblematerial such, for example, as a thin plastic film or sheet, wovenfabric, and the like on which a thin continuous deposit or coating hasbeen formed rendering the normally non-conducting material capable ofcarrying an electrical current. A cloth fabric woven from threads ofnatural or synthetic origin or from a mixture of both is particularlywell suited to such use and electrically conductive properties can bereadily imparted to it in the manner suggested above.

One of the problems frequently encountered in the use of suchelectrically conductive flexible material, however, has been thedifliculty experienced in satisfactorily securing electrical conductorsor connections to the electrically conductive material itself.

Such connections, while they can be accomplished by soldering orbrazing, are exceedingly bulky and susceptible to parting or breaking,especially where the connections are subjected in the normal use of theelectrically conductive flexible material to vibrations of highfrequency. Conditions of this nature are found, for example, in the useof such treated material in the fabrication of de-icing equipment foraircraft and the like. This represents only one of many such uses forthe material possessing comparable conditions affecting the security ofelectrical connections thereto.

It is, therefore, an object of the present invention to obviate any andall such difficulties as are encountered in the provision of a secureelectrical connection to the fabric by an improved method of forming theflexible material itself.

It is a further object of the present invention to provide anelectrically conductive material in which the strands comprising theelectrical conductors are intimately secured to or formed integrallywith the material itself, thereby producing a completely homogeneousproduct.

Other objects and advantages of the invention will become apparent asthe following description of one specific application of the inventiveconcept proceeds.

Fig. 1 represents a partial plan view of a segment of a composite clothfabric of the type 2 employed to advantage in the practice of thepresent invention. Fig. 2 illustrates the composite fabric of Fig. l towhich a coating of an electrically conductive material and a dressinghas been applied with an electrical circuit shown diagrammatically. Fig.3 is a fragmentary enlarged cross section of an article, for example, aheating element comprising a core of material such as that shown in Fig.2 and exposed laminae .Q insulating material. Fig. 4 shows a plasticfilm having metallic conductors attached and coated with an electricallyconductive material. Fig. 5 is an enlarged cross section of the articleshown in Fig. 4 and taken along the line 55 therein. Fig. 6 is adiagrammatic representation of an electrical circuit especially adaptedto use with the article illustrated in Fig. 4.

In Fig. 1 of the drawings, the reference numeral I identifies acomposite structure or fabric. The composite fabric I is made up of aplurality of weft or woof threads 2 extending transversely of thematerial and a plurality of warp threads 3 extending in a longitudinaldirection or normal to the woof. At or adjacent the edges of thecomposite fabric I, a plurality of metal wires or strands ofelectrically conductive material such, for example, as the metal Wires 4are substituted for certain of the warp threads so as to provide adistinct area, strip, or selvage 5 in the body of the fabric.

It will be readily understood that the metal wires 4 may extend ineither direction and, moreover, may be arranged together in spacedgroups or areas, each advantageously including a plurality of strands,throughout the body of the material depending upon the use to which thecomposite fabric I is to be put. Moreover, the metal strands or wires 4can be sewn or otherwise secured to the fabric in restricted areasthereof. In any event, it should be understood that the use of the stripor selvage' 5 adjacent the edge of the composite fabric I is found to beadvantageous for certain specific uses to which the material is to beput, but is by no means restrictive of the invention.

The core 5 illustrated in Fig. 2 represents the composite fabric I towhich a sheath or coating 1 has been applied. This sheath or coatingembodies an electrically conductive substance which is intimately bondedto the woof and warp threads 2 and 3, as well as to the metal wires 4 soas to form a homogeneous covering over the entire width of the compositefabric, but not necessarily filling the voids in the fabric. The wires 4forming the selvage portion 5 of the composite fabric 3 I are adapted tobe compacted, twisted, or gathered together in the manner indicated bythe reference numeral 8 so as to provide a satisfactory connection forthe electrical conductors 9 and I6 between which is disposed a source ofelectrical energy such, for example, as the battery I. The clips I4 and|5 may advantageously be employed to vfacilitate the connection of theconductors 9 and to the ends of the individual groups or gathers 8 ofthe wires at the ends of the selvage portions 5.

The electrically conductive substance used in the coating 1 applied tothe composite tab'ric I may take any of several forms. ,It may take theform of a chemically deposited metallic sub"- stance, such as metallicsilver deposited frcr'n a silver nitrate solution. A coating'i of copperer other suitable electrically conductive 'r'netals may be formed on thecomponents of the composite fabric by an electrochemical or platingprocess. It is essential that a substantially continuous sheath orcoating be formed ever the composite fabric I so as to insure a uniformparticle-toparticle contact over the entire surface "of the fabric.Other external dressings maybe applied over the coating 1. I I

The completed core 6 is particularly well suited to incor oration in alaminated structure in which the cure is completely enclosed in sheathsof suitable insulating and moisture resistant .-l-flt terial l2 and -|3as indicated in Fig. 3. These sheaths of insulating material i2 and i3may advantageously be relatively thin layers or vulcanized orunvulcanize'd rubber v'vh'i'ch, in the latter instance, are subsequentlyvulcanized. This construction is particularly well adapted to be afix'edby 'a suitable bonding agent to a surface, such, for example, as that ofa propeller or the wing surfaces of an airplane. Electrical current thensuppliedL to the core 8 or the completed structure It serves tofacilitate the removal cf ice collecting upon exposed surface.

-In Figs. 4, '5, and *6 is shown another type of "flexible material, inthis instance, a thin plastic film or sheet. The referencenumeral l'lgenerally identifies the composite structure. The composite structureembodies a plastic sheet 18 which carries a plurality "of continuouselectrically conducting strands or wires t9 arranged in a plurality ofspaced mutually parallel :gr'o'ups 2|), 2|, 22, 23, the whole beingcovered with a uniform coating 24 of an electrically conductivesubstance such, .for example, as 'a metal of the ;class includingsilver, gold, copper, and the like ortheir alloys. The individual 'wiresH), which must be exposed, are advantageously secured to the plastic"sheet 18 as by means of a thin :layer of an --elem'ent -or other typeof electrical unit.

With a composite structure of the type illustrated in Fig. 4 of thedrawings, the several groups 20, 2|, 22, and 23 set up a complexelectrical circuit diagrammatically illustrated in Fig. 6. In otherwords, the plastic sheet H! of the composite structure I! with thecoating 24 comprises a plate resistor in cooperation with the severalgroups 20, 2|, 22, and 23 of wires |9. Thus, a series of mutuallyparallel circuits is formed rm/owing the several groups 26, 2|, 22, and23, as shown in Fi 6.

The several cooperating groups 20 and 2|, 2| and 22, 22 and 23 representindividual mutually parallel resistances. The resistance circuit 29represents that set up on the coated plastic sheet 18 between thejc'ooperating groups 29 and 2| of the wires l9. "The resistance 30represents the completed circuit across the coated plastic sheet l8between the groups 2| and 22. Similarly, the resistance 3! representsthe completed circuit across the coated plastic sheet between groups 22and 23 of Wires l9.

'Ma-ny other highly advantageous uses of the material will readilysuggest themselves to those skilled in the art such, for example, asheating wall panels, enclosures for oil tanks to insure elevatedtemperatures of the contents, heated clothing, and 'm-any other similaruses. It will be understood that while certain representativeembodiments and details have been shown for the purpose of illustratingthe invention, it will be apparent to those skilled in this art thatvarious changes and modifications may be made therein without departingfrom the spirit or scope or the invention.

1 claim:

A n electrically conductive material ccmpri'sin'g a woven fabric ofnormally ncn-conductix e warp and woof threads with'certa-in of the warpthreads at least two -'spaced mutually parallel areas of the fabri'eadjac'ent the edges thereof being replaced by substantially continuousline wires having electrically conductive properties to form a compositefabric with integrally formed strips of metal thereingand a uniformcoating of an electrically conductive metal extending over both thenon-conductive threads and the conductive wires in the compositefabri'c.

. CHARLES J.

References Cited. in the file of this patent UNITED STATES PATENTS Nu-nicer Name Date Modal. l leath Nov. '16, I909 inseam nimble Jan. 29,19st 2305,54; Rideau et al. June 25, T9 11) -2r,27 l,;8fltl lviarick eta1. a Mar. '3, 1942 2,327,756 Adamson Aug. 24, 1943 2,386,095 Edgar etall. 00 13. 2, 1 945 anodes? Griffith et-al. Aug. 27,1946 2, 4;7' 3,l.33 Watson June 14,1949 2, i' 0i, l 5 '7 $pe ir e't-al. Apr. 11, I9502,5594) Johnson et a1. July 3-, :1 2,631,219 Suchy Mar. 1O, I953FGREZEGN PATENTS l luziiber "Country Date 581,212 Great "Britain Oct. 4,T946

